You can try setting up a separate instance that runs a recent version of Odoo (… like Odoo 9 ), and setup Bahmni to sync data there and see how it goes.
…maybe this post can help.
-This is not however for production servers and you would also have some work migrating your current data from OpenERP 7 to Odoo 9 if it’s about upgrading a production server… there will fore sure be a migration path provided once there is an official Bahmni release that installs a recent version of Odoo.